[PATCH] lsm: constify 'file' parameter in security_bprm_creds_from_file()

[Khadija Kamran <kamrankhadijadj@gmail.com>]

The 'bprm_creds_from_file' hook has implementation registered in
commoncap. Looking at the function implementation we observe that the
'file' parameter is not changing.

Mark the 'file' parameter of LSM hook security_bprm_creds_from_file() as
'const' since it will not be changing in the LSM hook.

Signed-off-by: Khadija Kamran <kamrankhadijadj@gmail.com>
---
 include/linux/fs.h            | 2 +-
 include/linux/lsm_hook_defs.h | 2 +-
 include/linux/security.h      | 6 +++---
 security/commoncap.c          | 4 ++--
 security/security.c           | 2 +-
 5 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 133f0640fb24..15d58978efea 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2314,7 +2314,7 @@ struct filename {
 };
 static_assert(offsetof(struct filename, iname) % sizeof(long) == 0);
 
-static inline struct mnt_idmap *file_mnt_idmap(struct file *file)
+static inline struct mnt_idmap *file_mnt_idmap(const struct file *file)
 {
 	return mnt_idmap(file->f_path.mnt);
 }
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 6bb55e61e8e8..1a05d95148e9 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -50,7 +50,7 @@ LSM_HOOK(int, 0, settime, const struct timespec64 *ts,
 	 const struct timezone *tz)
 LSM_HOOK(int, 0, vm_enough_memory, struct mm_struct *mm, long pages)
 LSM_HOOK(int, 0, bprm_creds_for_exec, struct linux_binprm *bprm)
-LSM_HOOK(int, 0, bprm_creds_from_file, struct linux_binprm *bprm, struct file *file)
+LSM_HOOK(int, 0, bprm_creds_from_file, struct linux_binprm *bprm, const struct file *file)
 LSM_HOOK(int, 0, bprm_check_security, struct linux_binprm *bprm)
 LSM_HOOK(void, LSM_RET_VOID, bprm_committing_creds, struct linux_binprm *bprm)
 LSM_HOOK(void, LSM_RET_VOID, bprm_committed_creds, struct linux_binprm *bprm)
diff --git a/include/linux/security.h b/include/linux/security.h
index e2734e9e44d5..fbd498046e39 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -150,7 +150,7 @@ extern int cap_capset(struct cred *new, const struct cred *old,
 		      const kernel_cap_t *effective,
 		      const kernel_cap_t *inheritable,
 		      const kernel_cap_t *permitted);
-extern int cap_bprm_creds_from_file(struct linux_binprm *bprm, struct file *file);
+extern int cap_bprm_creds_from_file(struct linux_binprm *bprm, const struct file *file);
 int cap_inode_setxattr(struct dentry *dentry, const char *name,
 		       const void *value, size_t size, int flags);
 int cap_inode_removexattr(struct mnt_idmap *idmap,
@@ -289,7 +289,7 @@ int security_syslog(int type);
 int security_settime64(const struct timespec64 *ts, const struct timezone *tz);
 int security_vm_enough_memory_mm(struct mm_struct *mm, long pages);
 int security_bprm_creds_for_exec(struct linux_binprm *bprm);
-int security_bprm_creds_from_file(struct linux_binprm *bprm, struct file *file);
+int security_bprm_creds_from_file(struct linux_binprm *bprm, const struct file *file);
 int security_bprm_check(struct linux_binprm *bprm);
 void security_bprm_committing_creds(struct linux_binprm *bprm);
 void security_bprm_committed_creds(struct linux_binprm *bprm);
@@ -611,7 +611,7 @@ static inline int security_bprm_creds_for_exec(struct linux_binprm *bprm)
 }
 
 static inline int security_bprm_creds_from_file(struct linux_binprm *bprm,
-						struct file *file)
+						const struct file *file)
 {
 	return cap_bprm_creds_from_file(bprm, file);
 }
diff --git a/security/commoncap.c b/security/commoncap.c
index 0b3fc2f3afe7..02a778257e2c 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -720,7 +720,7 @@ int get_vfs_caps_from_disk(struct mnt_idmap *idmap,
  * its xattrs and, if present, apply them to the proposed credentials being
  * constructed by execve().
  */
-static int get_file_caps(struct linux_binprm *bprm, struct file *file,
+static int get_file_caps(struct linux_binprm *bprm, const struct file *file,
 			 bool *effective, bool *has_fcap)
 {
 	int rc = 0;
@@ -882,7 +882,7 @@ static inline bool nonroot_raised_pE(struct cred *new, const struct cred *old,
  *
  * Return: 0 if successful, -ve on error.
  */
-int cap_bprm_creds_from_file(struct linux_binprm *bprm, struct file *file)
+int cap_bprm_creds_from_file(struct linux_binprm *bprm, const struct file *file)
 {
 	/* Process setpcap binaries and capabilities for uid 0 */
 	const struct cred *old = current_cred();
diff --git a/security/security.c b/security/security.c
index d5ff7ff45b77..bf7de5211542 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1078,7 +1078,7 @@ int security_bprm_creds_for_exec(struct linux_binprm *bprm)
  *
  * Return: Returns 0 if the hook is successful and permission is granted.
  */
-int security_bprm_creds_from_file(struct linux_binprm *bprm, struct file *file)
+int security_bprm_creds_from_file(struct linux_binprm *bprm, const struct file *file)
 {
 	return call_int_hook(bprm_creds_from_file, 0, bprm, file);
 }
-- 
2.34.1